Method of treating sulfid ores as lead-zinc ores



UNITED STATES PATENT OFFICE.

SOLOMON GANELIN, OF PHILADELPHIA, PENNSYLVANIA.

METHOD OF TREATING SULFID OFEES AS LEAD-ZINC ORES.

SPECIFICATION forming part of Letters Patent N 0. 593,415, dated November 9, 1897.

Application filed May 7, 1897. Serial No. 635,585. (No specimens.)

vented a certain new and useful Method of- Treating Sulfid Ores as Lead-Zinc Ores, of which the following is a specification.

My invention is based on a reaction of which I believe myself to be the discoverer and which consists in the following: Lead sulfid or galena if brought in contact with or stirred into a molten mass of a halogen salt of most of the metalsas, for example, zinc, cadmium, manganese, aluminium, magnesium, &c., (the metals of the alkali excluded,)a double decomposition takes place, the lead of the galena combining with the halogen radical of the molten salt and the metal of the latter combining with the sulfur of the galena according to the following equation:

As stated, this reaction takes place when the halogen salt of the metal is used in a molten state and when water is not present. In the latter case no reaction could take place, because in water the reaction between the four substances named goes on in the reverse direction. For example:

The reason for this I suppose is due to the fact that the halogen compounds of lead are more stable in the absence of water, while the halogen salts of most of the other metals are more stable in a Water solution, which can be seen from the heat of formation of the halogen compounds of lead compared with other metals when in absence of water and when in abundance of water. For example:

Zn+Ol :ZnCl +97,21O calories Zn-l- Cl in water:ZnOl l-112,840 calories Pb+Gl :PbOl +82,77O

Pb-i-Ol in water PbOl +7 5,970.

It is evident that in the absence of water the reaction will be in favor of forming lead chlorid and zinc sulfid, while in presence of water the reaction will go in the reverse direction, forming lead sulfid and zinc chlorid. In the first case (in absence of Water) heat will be liberated, when the sulfid of lead and the chlorid of zinc will change their acid radicals:

2O 97 82 ll PbS+ZnOl :PbOl +ZnS.

The gain will be about SlX thousand calories. In the lastcase, (in presence of water,) on the contrary, heat will be liberated, when zinc sulfid and lead chlorid will change their acid radicals, forming lead sulfid and zinc chlorid:

The gain will be about sixteen thousand calories. In the foregoing equations the heat of formation of each substance is stated in thousands. On this reaction is based my invention; and one of its objects is to provide a practically efiicient method for reducing leadzinc-sulfid ores. a

To this end my invention, generally stated, consists in introducing the powdered ore into a molten bath of a halogen salt of a metal, especially into a molten bath of the chlorids of many metals, whereby the lead sulfid of the ore is decomposed, its sulfur combining with the base of the salt of the molten bath and the halogen radical of the bath combining with the lead, so that there is produced in the bath a halogen salt of lead, which may be recovered therefrom by the process of recrystallization or reduced to the metallic state by the introduction of a metal more basic than lead into the molten bath, as is hereinafter more fully described and claimed, and a sulfid of the base of the salt that constituted the bath into which the ore was placed.

Another object of my invention is to provide at the same time a method of preparing the sulfids of most of the metals from their halogen compounds by means of lead sulfid or galena by stirring the latter into a molten bath of a halogen compound of the metal the sulfid of which is to be prepared.

The lead-zinc ores cannot be reduced by the ordinary processes which exist for recovering lead zinc on account of the interference of zinc with the ordinary processes for smelting lead, as well as on account of the impossibility of distilling the ores for Zinc on account of corrosion of the retort by the lead. In the practice of my invention I separate'the lead from the blende, recovering the lead either as lead chlorid or as metallic lead and obtaining V the zinc-blende as such, even more concentrated, in a manner which I shall now proceed to describe.

Ground ore is stirred into a fused mass of a metal chlorid free from water. I prefer to use zinc chlorid. The reaction commences immediately and double decomposition takes place between the lead sulfid or galena present in the ore and the fused zinc chlorid, resulting, as stated above, in the formation of zincsulfid or blende and lead chlorid,1both in an amountsubstantially equivalent to the galena :present in the ore. I thus obtain instead of the original lead-zinc sulfid ore what may be called zinc-blende ore containing the amount of zinc-blende which was present in the ores plus the zinc-blende formed in the reaction, all this mixed with the same ingredients or 'impuritiesfor example, pyrites, FeS and silicious compoundswhich were contained in the original ore. The lead which was present in the ore as lead sulfid is now combined with the chlorin that formed part of the molten chlorid of zinc-bath, thus forming leadchlorid. In other words, instead of the original lead-zinc ore I obtain zincblende in a fused mass of lead chlorid, together with some zinc chlorid in case the latter was taken in excess of the equivalent of the lead of the galena present in the lore. The further treatment may be carried on in different Ways.

First. Metallic zinc maybe stirred into the fused mass, and this metallic zinc reduces the llead chlorid to lead, forming zinc chlorid. The lead thus separated is in a molten state and collects at the bottom of the vesseland may ibedrawn oif therefrom. Afterward the mass of zinc-blende and zinc chlorid may .be removed from the vessel and permitted to cool, whereupon the mass maybe broken up into comparatively small pieces and systematica'lly leached with water, whereby the Zinc chlorid is removed. The solution of zinc chlorid thus obtained may be concentrated and evaporated to dryness and used again for making the fused bath of zinc chlorid, into which .the ground ore is first placed. Care should be taken that the fused bath of chlorid of zincis substantially free from water. The zinc-blende obtained after the,leach ingprocess and by the removal of 'the zinc chlorid and other soluble salts which may have been present in "the mixture may be treated for the recovery of metallic zinc in any known or preferred manner.

Second. After the reaction between the galena present in the ore ,and the fused zinc chlorid has taken place, asabove described, the whole mass is removed from the vessel and permitted to cool, and the lead chlorid is separated from the insoluble matter by recrystallization of the former. The lead chlorid obtained by such recrystallization maybe treated in any preferred or well-known manner for the recovery of metallic lead. The zinc-blende left may be reduced in any usual or preferred manner for the production of metallic zinc.

In the foregoing description I have described the introduction of powdered leadzinc ores into a fused mass or bath of zinc chlorid which should be free from water, but I have ascertained by experiment that the presence of other chlorids, as sodium chlorid and potassium chlorid, does not prevent the action of the fused zinc chlorid upon the galena of the ore, and the presenceof such other chlorids increases the bulk of the solutionand also increases the fluidity of the fused mass or bath, which is an advantageous feature because it facilitates the operation of stirring the powdered ore into the fused mass or bath. Moreover, zinc chlorid is more .conveniently freed from water which would be present-for example, after the Jeachingoperation hereinabove referred toe-in the presence of sodium chlorid and potassium chlorid.

In the foregoing description reference has been made particularly to the desulfur-ization of galena; but it has also been stated that the halogen saltor salts, ,as-chlorid of zinc, which constituted the bath, was converted into sulfid. Such conversion into sulfid is nsef ul, and the invention may be practiced, primarily, :for itsaccom-plishment. For example, the intro duction of lead sulfid into a molten massor bath of cryolite (double fluorid of aluminium and sodium) results in the production of lead and sodium fluorid and aluminium sulfid, which is useful in the arts.

Having thus described the nature and .objects of my invention, what Iclaim ,as new, and desire to secure .by Letters Patent, is

l. The process of treating orescontaining lead sulfid which consists in preparing a mass or bath of a fused halogen salt, capable of being decomposed by said sulfid, and introducing saidsulfid ore into said fused bath and thereby .efiecting double decomposition between the lead sulfidof the ore and halogen salt of the bath whereby conversion .of the lead sulfid of the ore into a halogen salt of lead and of the base of the halogensalt of the bath into a sulfid, are effected, substantially as described.

2. The processof treating lead-zinc-sulfid ores for the separation of lead compounds and zinc compounds which consists in introducing the lead-zinc-sulfid ore into a mass or bath of fused chlorids capable of being decomposed by said sulfid and thereby effecting double a decomposition between the lead-sulfid of the ore and chlorids of the bath and converting the lead sulfid of the ore into chlorid of lead and the chlorids of the fused bath or mass into sulfids and permitting the zincsulfid of the sulfid ore to remain in the fused bath or mass, substantially as described.

3. The method of treating ores in which galena is present which consists in introducing the ore into a fused mass or bath containing zinc chlorid and thereby converting the galena into chlorid of lead and form a sulfid of zinc, and then reducing the formed lead chlorid to the metallic state by the introduction of metallic zinc into the fused bath or mass, substantially as described.

4:. The process of forming sulfids of metals from such of their halogen compounds as are capable when fused of being decomposed by galena which consists in introducing galena I 5 In testimony whereof I have hereunto 2o signed my name.

' SOLOMON GANELIN;

In presence of- K. M. GILLIGAN, W. J. JAoKsoN. 

